Distance-to-fault (DTF) generally refers to analyzing the performance of a communication medium, such as a transmission line or antenna. DTF typically employs time domain reflectometry (TDR) or frequency domain reflectometry (FDR), which allows for fault isolation in a transmission system by identifying the presence and location of signal path impairment (e.g., damaged transmission line or connector, loose connection, faulty component, etc). In short, such impairments can cause unwanted signal reflections, which in turn diminish the performance of the communication system. Thus, using DTF to identify impairments can improve system performance.
One effective way to characterize transmission systems, electrical networks, and other such linear networks is by scattering parameters (S-parameters), which can be obtained by measurements of a vector network analyzer. In this sense, a vector network analyzer can be used in carrying out DTF analysis. In particular, a vector network analyzer can be used to analyze magnitude and phase characteristics of transmission systems and electrical networks, which are characteristics associated with the reflection and transmission of electrical signals. A typical vector network analyzer can perform simultaneous transmission and reflection S-parameter measurements, complex impedance measurements, TDR and FDR measurements.
Unfortunately, vector network analyzers tend to be expensive and are generally bulky and heavy. There is a need, therefore, for cost effective and/or low bulk DTF techniques that allow for accurate measurement of complex reflection coefficients.